1. Field of the Invention
The invention relates to a method for cooling a room by radiant heat exchange and to an apparatus for carrying out the method.
2. Description of the Related Art
It is known (see for example H. Sokolean: "Kuhldeckentechnologie zur Erreichung des bestmoglichen Raumkomforts", [Cooling-ceiling technology for achieving the best possible interior conditions], Architektur und Technik August 1992, p. 49-53, B+L Verlags AG, Schlieren (Switzerland)), to cool rooms by means of cooling elements which are preferably arranged in the ceiling area and through which usually there flows a heat transfer medium cooled in a central refrigerating unit. In this case, the cooling takes place by convective heat exchange of the cooling element with the air in the room and in particular by direct radiation exchange of the same with the objects located in the room.
The cooling capacity of such cooling elements is limited by the fact that their surface temperature must not drop below the dew point, since otherwise condensate forms during the cooling phases, which usually coincide with the times during which the room is in use. Although it has been proposed (WO-A-91/13 294) to cool below the dew point and to drain the condensate produced away by means of condensate channels or trays, it must be assumed that the formation of condensate during use of the climatically conditioned room is always problematical and undesired.
Also known (from DE-A-28 02 550) is a device for drying and cooling air in which the air is sucked by means of a fan over a cooling element which is temporarily cooled below the freezing point and which is freed of deposited frost by heating during short regeneration phases. However, such devices are not suitable for use in a room to be climatically conditioned and would therefore require air to be transported by forced convection, which would have to cause undesired draughts.
Since the dew point at the usually prevailing atmospheric moisture levels is around 12.degree. C. to 15.degree. C., if the formation of condensate is to be avoided in the case of a conventional cooling element arranged in the room to be cooled, the difference between the permissible temperature of the said element and the desired room temperature of about 22.degree. C. is very small and the cooling capacity which can be achieved is correspondingly modest. As a result, very large cooled surfaces are required, which entails comparatively high costs and has the effect of restricting interior design possibilities.